Can someone answer this question please answer it correctly if it’s corect I will mark you brainliest

Answer:
Semicolon
Explanation:
These are two separate phrases and need to be separated with a period or a semicolon.
Answer:
Scientists believe tornadoes form due to high relative humidity and significant wind changes in the lowest regions of the atmosphere ; furthermore tornadoes only form if downdrafts are present in just the right part of the storm.